Hunan Rice Research Institute, Key Laboratory of Indica Rice Genetics and Breeding in the Middle and Lower Reaches of Yangtze River Valley, Ministry of Agriculture, Changsha 410125, China.
Hunan Key Laboratory of Plant Functional Genomics and Developmental Regulation, College of Biology, Hunan University, Changsha 410082, China.
Int J Mol Sci. 2020 Mar 9;21(5):1857. doi: 10.3390/ijms21051857.
Drought is a serious problem, which causes heavy yield losses for rice. Heat-shock factors (HSFs) had been implicated in tolerance to drought and high temperature. However, there has not been much functional characterization and mechanism clarification in rice. Previously, we found an HSF gene, , was highly related with drought tolerance after screening from 10,000 different samples. Herein, we cloned the from rice and overexpressed it in to study its regulatory mechanism of drought tolerance. Phenotypic and physiological assays of the transgenic lines showed that overexpression of confers drought tolerance by reducing water loss and reactive oxygen species (ROS) levels, whereas it increases abscisic acid (ABA) levels. However, enzymatic antioxidants such as activity levels of superoxide dismutase, peroxidase and catalase were not significantly different between wild type and transgenic lines. Instead, we observed a significant increase in polyamine content, which was correlated with increased and expression levels. In silico and in vivo analyses confirmed that is a nuclear-localized gene. In addition, can bind to the promoter of and via a yeast one-hybrid assay. Overall, this study reveals that improves drought tolerance in not only by increasing ABA levels, but also by modulating polyamine levels to maintain ROS homeostasis, therefore it could be a strong candidate to develop drought-tolerant rice cultivars.
干旱是一个严重的问题，它会导致水稻严重减产。热休克因子（HSFs）被认为与耐旱和耐高温有关。然而，在水稻中，其功能特征和机制还没有得到充分的阐明。之前，我们从 10000 个不同的样本中筛选出一个与耐旱性高度相关的 HSF 基因 ，。在此，我们从水稻中克隆了 ，并在 中过表达它，以研究其耐旱性的调控机制。转基因 株系的表型和生理测定表明，过表达 可以通过降低水分损失和活性氧（ROS）水平来赋予耐旱性，同时增加脱落酸（ABA）水平。然而，超氧化物歧化酶、过氧化物酶和过氧化氢酶等酶促抗氧化剂的活性水平在野生型和转基因株系之间没有显著差异。相反，我们观察到多胺含量显著增加，这与 和 表达水平的增加有关。计算机分析和体内分析证实 是一个核定位基因。此外，酵母单杂交实验表明 可以与 和 的启动子结合。总的来说，这项研究表明， 不仅通过增加 ABA 水平，而且通过调节多胺水平来维持 ROS 稳态，从而提高 的耐旱性，因此它可能是培育耐旱水稻品种的一个有力候选基因。
